New Parkinson's Disease Drug Approved

Darrell Hulisz, RPh, PharmDAngelo Palmer

May 4, 2017

More than 10 million people worldwide have Parkinson's disease (PD) and approximately 60,000 Americans are diagnosed with PD each year. The Food and Drug Administration (FDA) recently approved safinamide (Xadago) tablets as add-on treatment to leveodopa/carbidopa for patients with PD who are experiencing "off" episodes. "Off" episodes are the period of time that the primary PD drugs, such as levodopa/carbidopa stop working. According to a recent release, patients receiving safinamide experienced more beneficial "on" time. The medication has already been available in Europe for some time now and is now making its way to the U.S. markets. Safinamide is the first new Parkinson's drug approved by the FDA in more than a decade.

Safinamide is a new chemical entity with a mode of action characterized by selective MAO-B inhibition. Other MAO-B inhibitors for PD include selegeline and rasagiline. Inhibition of MAO-B activity, by blocking the catabolism of dopamine, is thought to result in an increase in dopamine levels and a subsequent increase in dopaminergic activity in the brain.Data from two double-blind, placebo-controlled trials have demonstrated that the drug produces statistically significant increases in "on" time without troublesome dyskinesia, as well as a decrease in "off" time. Safinamide has not been shown to be effective as monotherapy for the treatment of PD. The recommended dose is to initiate with 50 mg administered orally once daily at the same time of day; after two weeks, the dose may be increased to 100 mg once daily, based on individual need and tolerability. The drug was FDA approved in March 2017 & will be available as 50 mg and 100 mg tablets.

The most common adverse reactions observed in patients taking safinamide were uncontrolled involuntary movement, falls, nausea, insomnia. Additionally, patients who have severe liver problems, or who take dextromethorphan should not take safinamide. It should also not be taken by patients who take monoamine oxidase inhibitors (MAOI) or by those who take an opioid drug, St. John's wort, linezolid, serotonin-norepinephrine re-uptake inhibitors, tricyclic antidepressants and cyclobenzaprine.

Because levodopa remains one of the most effective tools in treating PD and is prescribed to a large portion of this population, health care professionals need to monitor for the potential long-term treatment adverse effects of levodopa/carbidopa, such as debilitating motor fluctuations. As the disease progresses, additional medications are typically added to levodopa/carbidopa to help patients cope with increasing "off" episodes. However, the exact role for safinamide and advantages over other MAO-B inhibitors remain to be determined.